The proposed research is aimed at understanding the fate and transport of selected Superfund chemicals, their concentration exceedence probabilities in surface and ground waters, and related human and wildlife exposure in areas surrounding the FCX, Inc. Superfund site in Washington, NC and the Georgia-Pacific Corporation Hardwood Sawhill Superfund site in Plymouth, NC. A multi-scale approach will be applied to the characterization of field scale contaminant fate and transport and direct linkages between laboratory, field, and modeling studies will be forged. A baseline with respect to field scale environmental behavior will be established using an innocuous sorbing tracer bearing structural resemblance to the selected Superfund chemicals. Field scale environmental behavior of Superfund field sites will then be extrapolated from this baseline. In Phase I, the surface and subsurface in and around the two Superfund field sites will be characterized at the spectroscopic, batch, column, and field scales and related physico-chemical properties will be estimated. In Phase II, abiotic interfacial processes expected to attenuate or mobilize the solute (tracer and contaminant) will be identified and batch equilibrium constants and reaction kinetics will be established. Solute mass transport will then be evaluate in column studies; inverse modeling will be employed to estimate the parameters describing equilibrium and non-equilibrium interfacial processes and linear and non-linear sorption/desorption phenomena. The observed similarities and differences in the environmental behavior of the tracer and test contaminants will be related to the physical-chemical properties and molecular structure of the solutes and spatial physico-chemical variability of the subsurface. The appropriate choice of model will be confirmed utilizing systematic comparisons of the parameter estimates and characterizations obtained from a range of models. Field tracer data will be used as a vehicle to upscale spectroscopic, batch, and column scale data on the test contaminants (and established interrelationships between tracer and contaminant environmental behavior) to the field scale. A field-scale stochastic fate and transport model with the capability to estimate concentration exceedence probabilities in groundwater and surface waters and related risk to human populations ecosystems will be formulated.